BUTTE, Mont. -- A single-engine turboprop airplane that crashed just short of Butte airport jerked to the left before nose-diving into a cemetery, killing all 14 people aboard, a witness said Monday.

Kenny Gulick, 14, told CBS' "The Early Show" on Monday that he thought he was watching a stunt plane because the pilot was making so many turns.

"He jerked the plane to the left too quickly and lost control of it, but that's just my guess," said Gulick. "And all of a sudden it went into a nosedive. I noticed the pilot trying to pull up but he was extremely low to the ground and he didn't pull up in time."

The death toll was confirmed by Karen Byrd, a Federal Aviation Administration operations officer in Renton, Wash. Earlier, the count had been put as high as 17.

The aircraft had departed from Oroville, Calif., and the pilot had filed a flight plan showing a destination of Bozeman, about 85 miles southeast of Butte. But the pilot canceled his flight plan at some point and headed for Butte, Fergus said.

The plane, a Pilatus PC-12, was believed to be taking its occupants on a ski trip to Montana. "We think that it was probably a ski trip for the kids," Fergus said.

The Pilatus PC-12's capacity is 12 adults. It was not known whether the extra people aboard was a factor in the crash, since seven of the victims were children.

An investigator with the National Transportation Safety Board offered few details at a press conference in Butte on Sunday night. No cause of the crash was given.

A California newspaper, the Napa Valley Register, reported on its Web site late Sunday that a family of five from St. Helena, Calif., including three preschoolers, was among the victims.

The Butte airport is among about 7,000 small airports around the country that have no radar coverage. A pilot approaching the airport would normally switch to a radio frequency used by aircraft coming in and out of Butte to find out if there were any other aircraft in the area. Then the pilot would use visual flight rules and follow the procedures for landing at that airport.

Steve Guidoni, of Butte, was driving by with his wife when he saw the crash. "It just went straight into the ground. I went over there to try to help. I thought maybe I would pull someone out of the fire."

Guidoni said he saw luggage and seat cushions lying around, but no bodies. He said the biggest piece of the plane was the size of a kitchen table. "You wouldn't even know a plane was there," he said.

Nick Dipasquale, 19, was working at a gas station across the street. "I heard a loud bang," he said. "It sounded like someone ran into the building."

NTSB investigator Kristi Dunks would not say if there had been a distress call from the pilot. It was partly cloudy, visibility was 10 miles and wind was blowing from the northwest around 10 mph at the time of the crash, according to the National Weather Service.

Butte Silver-Bow Sheriff John Walsh said there were a few people at the cemetery at the time of the crash, but no one on the ground was injured.

It was the worst plane crash in America since a commuter plane last month fell on a house in a suburb of Buffalo, N.Y., killing all 49 passengers and a man in the home. Before the Buffalo crash there hadn't been an accident involving a commercial airliner in the U.S. in which there were fatalities in more than two years.

The plane was registered to Eagle Cap Leasing Inc. in Enterprise, Ore., Fergus said. He didn't know who was operating the plane.

Felkamp is listed in Oregon corporate records as Eagle Cap's president. Attempts to reach him by phone were unsuccessful.

In Switzerland, Markus Kaelin, executive assistant to the chairman of Pilatus Aircraft, said the company had no comment.

The plane took off from Brown Field Municipal airport in San Diego on Saturday evening and flew to Redlands, Calif., about 100 miles north, said Rachel Laing, a spokeswoman for the city of San Diego.

It then left Sunday morning for Vacaville, Calif., according to Flight Aware, a Web-based service that tracks air traffic. From there it flew to Oroville, Calif., and on to Butte.